He coached the St. Mary's junior OHA team to its third-straight SPA junior championship in the 1924–25 season, with a team that included future Toronto Maple Leafs star Joe Primeau. In 1926–27, the team became the Toronto Marlboros, and again won the junior SPA championship. Eventual Hall of FamerRed Horner was a star defenceman on the Toronto team. During his time with the organization, Selke also coached the Marlboros senior team.

Selke became the top assistant to Maple Leafs managing director Conn Smythe in September 1929 — a position he would hold until 1946. He helped raise funds for the construction of Maple Leaf Gardens in 1931. While Smythe served in World War II, Selke filled in as acting manager of the Leafs and Maple Leaf Gardens. He did such a good job in that role that some of the directors of the company wanted him to remain in charge after Smythe returned.

Selke and Smythe clashed when Selke traded Frank Eddolls to the Montreal Canadiens for the rights to Ted Kennedy in 1943. Kennedy would go on to become one of Smythe's favourite Leafs, but at the time he was a big supporter of Eddolls and was upset that he hadn't been consulted before Selke made the deal. Once Smythe returned to Toronto, there was tension between the two, particularly after Selke wouldn't back Smythe's bid to become president of Maple Leaf Gardens Ltd. With his working conditions becoming intolerable, Selke turned in his resignation in May 1946.

Selke's son, Frank Selke Jr. (1929–2013), was also a noted executive and Publicity Director from 1951 to 1965. He was part of 6 Stanley Cup winning pictures in 1953 and 1956–60. However, his name does not appear on the Stanley Cup. He was the intermission host on Montreal Canadiens broadcasts for much of the 1960s and was president of the Oakland Seals (later known as the California Golden Seals). He became vice-president of the Canadian Sports Network.[citation needed]